Studies of neuroendocrine function in patients suffering affective disorders are designed to illuminate the nature of hypothalamic dysfunction in these conditions. The patterns of secretion and response to stimulation and suppression tests of cortisol, HGH, LH, and prolactin are being investigated in depressed patients before and after recovery. The prolactin responses to neuroleptic drugs in normals and schizophrenics serve as a useful test of brain dopamine blockade in man.